You can also choose casting as option for the metal frames,

but that would defeat the purpose of automation possibly.

 

And the technique, to create the shell in its entirety,

place the floor and walls enwrapped around it,

secure this with placement of bars from side angle,

and cut the required areas from outside of the wall.

then pouring the cement...

 

so building things in a.... modular (wall by wall, not brick by brick),

speedy way... instead little by little. and therefore leaving it to the machines.

because it is programmable/predictable steps.

labor costs involved, material costs involved... far less in this sense...